This invention relates to a magnetic tape cartridge, and more particularly, to a means for holding a leader tape within a leader block of a single reel tape cartridge.
Single reel tape cartridges are known in the art as evidenced by U.S. Pat. Nos. 4,383,660; 4,452,406; and 4,426,047, issued to RICHARD et al. More particularly, as shown in FIG. 1 included herewith, a single reel tape cartridge 10 includes a reel hub 12 containing a plurality of layers of a magnetic tape 14 with a leader block 16 attached to the free end or leader 15 of the tape 14 extending from the reel hub 12. A leader block window 18 permits the tape 14 to exit the tape cartridge 10 when the leader block 16 is removed from the corner 11 for threading through an external tape drive (not shown) when the leader block 16 is moved in the direction of the arrow 17. The window 18 is covered by the leader block 16 when the leader block 16 is snapped into a well 20 formed at the corner 11 of the tape cartridge 10, thus preventing contamination of the tape 14.
It is common in this art for the leader tape 15 to be mechanically fixed to the leader block 16 by a cylindrical pin or staking rod 22 fit into a corresponding opening 24 formed in the leader block 16. Several methods are known for introducing a staking rod 22 into the leader block 16.
For example, the leader tape 15 may be fixed to the leader block 16 by an extruded, round stock of ether-based polyurethane supplied in the form of a continuous roll. The stock is mechanically picked up and advanced to a position above the leader tape 15 and leader block 16. Next, the staking rod is cut free of the continuous roll and is forced into the opening 24 formed in the leader block 16 in a direction colinear with the axis of the opening.
The drawbacks of this method are as follows. First, an extruded staking rod is difficult to produce with accurate, round, outside diameters. Second, the process of winding the continuous extruded stock on spools is difficult to accomplish without unwanted stressing and stretching of the stock. Third, it is difficult to cut the stock consistently. Fourth, and most importantly, it is difficult to maintain adequate control of the stock/staking rod during cutting and insertion. This last drawback, combined with the sensitivity of the tape and the compression required to insert the staking rod 22 in the opening 24, lead to frequent problems, such as misoriented, damaged and broken tape.
U.S. Pat. No. 4,283,026, issued to WERNER, shows another method of securing the leader tape. According to this patent, a clamping member is pressed into an opening via a specially designed tool and withdrawn, if necessary, by a second, different tool. Since the leader tape is being pushed while the clamping member is being forced into the opening, this method is also characterized by misoriented, damaged or broken tape. In addition, this method is not efficiently adapted to automation because engagement and control of the clamping member is difficult. Of course, due to the high volume in which tape cartridges are sold, efficient automation is a prerequisite to the success of a method for inserting a staking rod.
U.S. Pat. No. 4,213,578, issued to KATATA, shows another method, including a tape locking piece which is also fit within an opening formed in a tape reel in a direction perpendicular to the axis of the opening. The tape locking device has an elongated elliptical cross-section, wherein the relatively straight sides are inserted adjacent the relatively narrow mouth of the opening and the device is turned to fit a wider inner portion of the opening. However, this method also does not lend itself efficiently to automation because it is difficult to control the tape locking device during insertion.
In light of the above, it is clear that a number of diverse methods are currently employed to secure leader tape within a leader block, each of which is characterized by a number of drawbacks from an automation point of view. As a result, a need still exists for a more efficient method.